/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hdfs.server.namenode;

import java.io.IOException;
import java.io.PrintWriter;
import java.security.PrivilegedExceptionAction;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.ContentSummary;
import org.apache.hadoop.hdfs.protocol.ClientProtocol;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.util.ServletUtil;
import org.znerd.xmlenc.XMLOutputter;

/** Servlets for file checksum */
public class ContentSummaryServlet extends DfsServlet {
	/** For java.io.Serializable */
	private static final long serialVersionUID = 1L;

	/** {@inheritDoc} */
	public void doGet(final HttpServletRequest request,
			final HttpServletResponse response) throws ServletException,
			IOException {
		final Configuration conf = (Configuration) getServletContext()
				.getAttribute(JspHelper.CURRENT_CONF);
		final UserGroupInformation ugi = getUGI(request, conf);
		try {
			ugi.doAs(new PrivilegedExceptionAction<Void>() {
				@Override
				public Void run() throws Exception {
					final String path = ServletUtil.getDecodedPath(request,
							"/contentSummary");
					final PrintWriter out = response.getWriter();
					final XMLOutputter xml = new XMLOutputter(out, "UTF-8");
					xml.declaration();
					try {
						// get content summary
						final ClientProtocol nnproxy = createNameNodeProxy();
						final ContentSummary cs = nnproxy
								.getContentSummary(path);

						// write xml
						xml.startTag(ContentSummary.class.getName());
						if (cs != null) {
							xml.attribute("length", "" + cs.getLength());
							xml.attribute("fileCount", "" + cs.getFileCount());
							xml.attribute("directoryCount",
									"" + cs.getDirectoryCount());
							xml.attribute("quota", "" + cs.getQuota());
							xml.attribute("spaceConsumed",
									"" + cs.getSpaceConsumed());
							xml.attribute("spaceQuota", "" + cs.getSpaceQuota());
						}
						xml.endTag();
					} catch (IOException ioe) {
						writeXml(ioe, path, xml);
					}
					xml.endDocument();
					return null;
				}
			});
		} catch (InterruptedException e) {
			throw new IOException(e);
		}
	}
}
